Japanese unexamined patent application publication No. 2003-72910 (Patent Document 1) discloses an example of the article transfer system noted above. In this article transfer system, the abnormality in the article transporting device or a target point to which the article is transferred by the article transporting device is detected at the abnormality detecting sensor. When the abnormality determination section determines that any abnormality occurs in the article transporting device or a target point to which the article is transferred by the article transporting device based on based on detecting information received from the abnormality detecting sensor, information indicating that the abnormality occurs in the article transporting device or a target point to which the article is transferred by the article transporting device is displayed on the display device as the abnormality occurrence information, thereby to notify the operator of the abnormality. As noted above, in the article transfer system of this type, the abnormality of the article transporting device or a target point to which the article is transferred by the article transporting device is detected at the abnormality detecting sensor. However, the abnormality detecting sensor may erroneously detect the abnormality due to a mechanical failure or an installment error of the abnormality detecting sensor even if no abnormality actually occurs in the article transporting device or a target point to which the article is transferred by the article transporting device, and the abnormality determination section may determine that the abnormality occurs in response to the erroneous detection.
The article transfer system disclosed in Patent Document 1 is designed to only notify the operator, even in the above-noted case, that the abnormality occurs by displaying the information on the display device indicating that the abnormality occurs in the article transporting device or a target point to which the article is transferred by the article transporting device as the abnormality occurrence information. Hence, the operator for using or supervising the article transfer system tends to realize less easily that the abnormality occurs in the abnormality detecting sensor, which may require a lot of time for adopting measures against the abnormality.